1. Field of the Invention
The present invention relates to a method and apparatus for packaging an article in a stretchable container. More particularly, the invention relates to a method and apparatus for packaging perishable living articles such as fresh fruit or vegetables in a stretchable wrapper for reducing moisture migration from the article while permitting gases such as oxygen and carbon dioxide to diffuse into and out of the package.
2. Description of the Prior Art
Packaging or wrapping an article between strips of stretchable wrapping material and thereafter heat sealing the strips together enabling the film to stretch tightly over the articles is broadly known in the art. U.S. patents such as Salfisberg U.S. Pat. No. 2,141,318; Vaughan U.S. Pat. No. 3,381,444 and Grasvoll U.S. Pat. No. 3,933,569 are representative of such systems.
It is broadly old to shrink wrap articles within plastic films which are heated, either before or after heat sealing, to soften the film causing the film to shrink and tightly conform to the shape of the article. U.S. patents such as Pfeiffer U.S. Pat. No. 2,486,759; Nicolle U.S. Pat. No. 2,494,484 and Horsky U.S. Pat. No. 3,851,440 are representative of this type of packaging.
It is recognized that fruit and vegetables or the like are living articles which live, after being severed from the plant, since they maintain life on the sugars and the like stored in the article itself. The metabolic activity of the article at this time is known as catabolism. Catabolism is a process which breaks down the food products from the living article to sustain life of the article while eliminating water from the article due to chemical activities. Thus, catabolism reduces the food value of the living article, while any means which will retard the self destruction of the catabolistic process maintains the desirable food elements in the living article for longer periods of time.
It is known that freshly harvested fruits and vegetables contain many vitamins and minerals needed by humans for good health and growth. It is also known that packaging such articles as soon as possible after harvest in a manner which reduces moisture loss, but permits oxygen to enter the package and carbon dioxide to exit the package at relatively slow rates will maintain the fruit in a fresh state for longer periods of time.